Can I add a PA sched UE for union dues after filing federal & state with you because they are still deductable for state and local?

Once your federal and state income tax returns are accepted, you would need to amend your PA state return to add PA Schedule UE.  If either return is rejected, you can go in and add the information to complete Schedule UE and attempt to re-file.  Don't do anything until you know the status of your return.